In order to minimize propeller weight, it is desirable to utilize narrow chord blades. Such blades must have high operating lift coefficients, however, to be able to develop required take-off thrust, and must have low operating lift coefficients required for efficient cruise operation. Such operating efficiency is particularly important for aircraft whose mission profile requires extensive loitering and high speed cruising.
Prior art propeller blades do not meet these requirements particularly for aircraft that cruise in the Mach 0.50 to 0.70 range. NACA Series 16 blades, in particular, may experience unacceptable shock losses at take-off, loiter and cruise speeds. Accordingly, new airfoil families for use in propeller blades are sought.